Nedelcu I, Crăciun D, Târdei G, Ruţă S M, Grancea C, Cernescu C
St. S. Nicolau Institute of Virology, Bucharest, Romania.
Rom J Virol. 1998 Jan-Dec;49(1-4):43-51.
In October 1995, The Ministry of Health has initiated the national immunization program of newborns against hepatitis B. Owing to the frequency of asymptomatic Hepatitis B clinical forms in children, as well as the deficiencies in the surveillance system, the assessment of the vaccination efficacy can be performed objectively only by the detection of the prevalence of anti HBs antibodies in children to whom the complete three doses of immunization schedule have been administered (at 0, 2 and 6 months of age). We report in this study the results of a seroprevalence research carried out on a group of 272 children from orphanages who have been vaccinated. A protective anti HBs titer (> 10 mIU) was recorded only in 66.3% of cases; other 10 samples contained antibodies at a titer lower than the protective level. In the 80 children without seroconversion the presence of anti HBc antibodies (marker for the natural infection) was investigated. 30% of the seronegative children have anti HBc antibodies from which 54.2% have also HbsAg. Significant differences were recorded in the seroconversion level and in the geometric mean of titers between the various units in which sera were collected. In four orphanages (district Arad, Jassy, Sibiu and Teleorman) the seroconversion exceeded 90%, in 5 orphanages it was over 80% and in the others it ranged from 30% to 70%. The lowest seroconversions were recorded in the orphanages in Bucharest, Botoşani, Galaţi and Olt. The possible causes of the low immunogenicity are analyzed: non-vaccination or incomplete vaccination; low immunoreactivity of children, many of whom are premature; high HbsAg carriage rate among the mother's etc. Although the evolution of the post vaccinal seroconversion is not a routine practice in the appraisement of Hepatitis B vaccine immunogenicity, our results require the extension of the study in order to adopt the most effective vaccinal strategy.
1995年10月，卫生部启动了新生儿乙型肝炎国家免疫规划。由于儿童无症状乙型肝炎临床形式的发生率以及监测系统的缺陷，只有通过检测已完成三剂免疫程序（0、2和6月龄）儿童的抗-HBs抗体流行率，才能客观地评估疫苗接种效果。我们在本研究中报告了对一组272名已接种疫苗的孤儿院儿童进行的血清流行率研究结果。仅66.3%的病例记录到保护性抗-HBs滴度（>10 mIU）；另外10份样本的抗体滴度低于保护水平。在80例未发生血清转化的儿童中，调查了抗-HBc抗体（自然感染标志物）的存在情况。30%的血清阴性儿童有抗-HBc抗体，其中54.2%也有HBsAg。在采集血清的不同单位之间，血清转化率和滴度几何平均值存在显著差异。在四个孤儿院（阿拉德、雅西、锡比乌和特尔戈维什泰地区），血清转化率超过90%，在5个孤儿院超过80%，在其他孤儿院则在30%至70%之间。最低的血清转化率记录在布加勒斯特、博托沙尼、加拉茨和奥尔特的孤儿院。分析了免疫原性低的可能原因：未接种或接种不完全；儿童免疫反应性低，其中许多是早产儿；母亲等人群中HBsAg携带率高。尽管疫苗接种后血清转化的演变在评估乙型肝炎疫苗免疫原性方面不是常规做法，但我们的结果需要扩大研究范围，以便采用最有效的疫苗接种策略。
